The purpose of this study was to obtain data on the immunogenicity of TTCalpt, a potential immuno-contraceptive vaccine, following intramuscular (IM) injection. The antigen TTCalpt, was prepared with 50 5g CGP11637 for emulsification in vehicle, with a total dosing volume of 0.5 ml for the initial injection. Two groups of three adult female cynomolgus received either 300 5g of TTCalpt initially, with a booster of 150 5g, ten days following the initial injection, or 100 5g of TTCalpt initially, followed by a booster of 50 5g, ten days following the initial injection for the high and low dose respectively. A second booster injection was administered using 0.1 ml of approximately 200 5g/0.5 ml mixture of the residual antigen from the original 300 and 100 5g dosing concentrations. All animals from both dose groups received the same concentration of antigen on study day 80 for the second booster injection. All injections were administered IM in the thigh. All animals were observed and no adverse signs were reported. Blood was collected once prior to each initial IM injection, then on day 10 prior to the first booster injection, then once per two week intervals for approximately five months. Antibody titers were measured on a monthly basis by Dr. Erwin Goldberg, Northwestern University, and blood collection was continued to study day 150, at which time the antibody titers were undetectable. *KEY*Immuno-contraception, Sperm antigens, Vaccine